206 E - A - Schäfer, 



published any detailed account of the appearances of these fibres after 

 treatment by this method, and has given only a single figure of a 

 wing'-sarcostyle, *) which, although representing a common appearance, 

 adds nothing to our knowledge of the structure of the fibres. It may 

 be as well, therefore, to describe their character somewhat fully. 



A large number of the sarcostjdes which are seen in these pre- 

 parations show a simple alternation of deeply stained reddish-violet 

 sarcous elements, separated from one another by narrow clear intervals 

 in which the membrane of Krause is not visible (Fig. 28, a). This 

 membrane, however, comes into view if the sarcous elements are 

 further removed from one another so that the clear interval is broader 

 (Fig. 28, b). Opposite the membrane there is generally a slight, but 

 sharply marked depression of the outline of the muscle-column which 

 is, in fact, at these places encircled by a notch of greater or less 

 depth (Fig. 31). The darkly stained sarcous element is distinctly 

 longitudinally striated, and in one instance I have seen evidence of 

 longitudinal splitting (Fig. 32). I have also been able to detect, 

 especially in photographs from these preparations, a very delicate longi- 

 tudinal striation in the clear intervals; with this exception these intervals 

 look like spaces having the appearance of being occupied by nothing 

 but watery fluid. The intersegmental membrane (membrane of Krause) 

 looks either like a fine homogeneous line crossing the thickness of the 

 fibre (Figs. 29, 34) or it has a dotted aspect as if it were alter- 

 nately thicker and thinner or as if composed of juxtaposed granules 

 (Fig. 30): this has also been described by Kölliker and others. The 

 longitudinal streaks of the clear intervals look like prolongations 

 of the substance of the sarcous elements which are attached to these 

 granules. I have never seen any indication of cleavage of the trans- 

 verse membranes into two. 



There is, as before said, a great amount of variability with regard 

 to the length of the clear spaces. Sometimes they are reduced to 

 thin intervals, which almost allow the successive sarcous elements to 

 come into contact and in which, as above mentioned, the membranes 

 of Krause cannot then be seen (Fig. 28, a). This is probably to be 



') Second communication, Taf. IV. Fig. 2. 



